Pete has pretty good advise, but a easier way is to take a drive. Get on a long straight road with little traffic. Get in second or third gear and run flat out for a decent amount of time, 1/4 mile or more, full rpm, just as if you are racing someone. When you are at top speed, push in the clutch and shut off the engine ASAP, and get off the road as quickly and safely as possible. Pull out a spark plug or two right there on the side of the road. If they are black, your carb is jetted to rich, if they are brown, just right, if they are white, to lean. You have to check them right there, any driving will alter the high rpm check.
For idle adjustment, get the truck up to temperature and remove the air filter, it does have a decent size filter doesn't it? not one of the 3" or 4" lawn mower filters, but a good sized factory filter. Anyway, adjust the idle screws in till it starts to shudder, a little on each one 1/4 turn at a time. Once both are in where it doesn't want to run, back them out 1/4 at a time till its running smooth. If you go to much it becomes rich yet still idles OK. Stay on the leaner side. It will take a few tries on each screw till you find the right spot. 1 1/2 turns out is usually pretty close.
You can lean a carb with bigger rods, smaller jets, or a combination of both. You can also lean down a jet size or so just by lowering the floats a bit. Thats a quick and easy fix, float adjustment. Go to low and you can get a high speed lean out.
Be sure the secondary's are full closed,
check float level,
check timing,( advanced more for better fuel economy),
check vacuum advance ( should be full time vacuum),
check fuel pressure ( to high will cause a rich condition).
Stock fuel pumps, OK, electric should be regulated down ,4-6 psi is all thats needed.
Since you changed carbs, have you had the truck on a long hard drive? It will take some time to dry out a whole exhaust system. Find you a long steep hill and make a bunch of high speed runs up it, thats a good way to really work a engine and get it really hot. If it still has dirty exhaust, after really working it, then its still rich and needs attention. A long 100 mile trip would do it some good also.
Joe
